In computer graphics display systems, elements displayed within a particular display image are referred to as display objects, or objects. In many computer graphics displays, it is required to provide tracked objects. A tracked object is an object which is displayed so as to reflect the movement of the object through the display space reflected by the display image.
For example, a tracked moving object may be displayed by displaying the current position of the object 100% of the time, while also displaying a number of previous positions of the object periodically in ascending sequential (temporal) order. The resulting effect is similar to that of a flashing detour sign as is typically used to direct automobile drivers toward a particular direction. The flashing detour sign flashes sequentially in the direction of the detour.
Tracked objects are useful in many graphics system applications, for example radar displays. The tracked object on a radar display can be used to show an observing radar officer the path of a moving object detected by the radar and its approximate speed.
In existing systems which provide tracked object displays, the computational resources required for these operations are dependent on the number of tracked objects within the screen display at any given time. This is because existing application programs have typically done the tracking directly through many layers of software within the existing system. Specifically, in such systems, in order to display a tracked object the application must draw, erase, and re-draw the object in its current and previous location in order to make it appear tracked.
Current systems are required to simultaneously display thousands of tracked objects. Such systems often must use 100% of their CPU power in order to maintain the large number of tracked objects on their displays. This high utilization of the CPU is undesirable and unacceptable where computational resources must be shared by multiple applications.
Thus there is required a new computer graphics system for displaying tracked objects which is capable of displaying large numbers of tracked objects simultaneously, which does not require high utilization of the CPU, and which preferably does not require an application software program to draw, erase, and redraw each tracked object.